Robot tool changers are known which include a first plate that is adapted to be connected to a robot arm and a second plate that is adapted to be connected to an end of the arm tool for the robot. In such arrangements, a coupling system is provided between the first and second plates for aligning the plates and connecting them together for securing the end of the arm tool to the robot arm and to provide a strong joint between the first and second plates during operation of the robot. An example of such a tool changer is set forth in U.S. Pat. No. 4,793,053 which is assigned to the assignee of the subject application.
In the '053 patent, a pair of deep draft frustoconical annular surfaces are provided therebetween to provide a strong non-tilt release joint between the first and second plates. The frustoconical surfaces have a depth and a bearing surface which prevents separation of the first and second plates other than along the Z axis or longitudinal axes of the connected plates.
Other devices are provided between the robot arm and an EOAT to prevent an overload force from being imposed on the robot arm during its operation. One such system is set forth U.S. Pat. No. 4,860,864 assigned to an assignee common to that of the present application.
In the '405 application, a magnet and a steel plate are connected between first and second plates of the device to maintain a magnetic attraction therebetween to complete a joint between a robot arm and an end of arm tool device. The magnetic force is broken to decouple the end of arm tool from the robot arm by providing cam surfaces on one of the plates and a tapered nest configuration on the opposite plate to cause the magnet to be separated from the steel plate insert on the other of the plates when one of the plates is moved torsionally along at least one of three coordinate linear axes when a load applied to the end of the arm device exceeds an overload force condition on the robot arm.
While the aforesaid robot tool changer of the '053 patent and the break away connection of the '405 application are suitable for their intended purposes, neither the tool changer device nor the break away device have the capability of performing the functional purpose of the other.